Wasm Compilation cleanup

Makefile

@@ -35,11 +35,13 @@ CFLAGS += -std=c11 -Wall -Wextra -Wdouble-promotion -Wvla -pedantic
 
 TARGET = $(lastword $(shell $(CC) -v 2>&1 | grep "Target: "))
 
+LIB_SHARED := true
 LIB_SUFFIX := so
 
 ifeq ($(TARGET),wasm32)
+  LIB_SHARED := false
   LIB_SUFFIX := wasm
-  CFLAGS += -mbulk-memory
+  CFLAGS += -Iwasm -mbulk-memory
   LDFLAGS += -nostdlib -Wl,--no-entry -Wl,--export-dynamic
 endif
 
@@ -148,8 +150,11 @@ $(BUILD_DIR)/%.o: %.cc $(MAKEFILE_DEPS)
 	    $(addprefix -I,$(INCLUDE)) \
 	    $(addprefix -D,$(DEFINE)) -MMD -MF $(@:.o=.d) -o $@
 
-$(LIB): CFLAGS += -fvisibility=hidden -flto -fPIC
-$(LIB): LDFLAGS += -flto -shared
+ifeq ($(LIB_SHARED),true)
+    $(LIB): CFLAGS += -fvisibility=hidden -flto -fPIC
+    $(LIB): LDFLAGS += -flto -shared
+endif
+
 $(LIB): $(MAKEFILE_DEPS)
 	@echo "  LD      $(notdir $@)"
 	$(V)mkdir -p $(dir $@)

README.md

@@ -61,6 +61,20 @@ $ make -j CC=path_to_android_ndk_prebuilt/toolchain-prefix-clang LIBC=bionic
 
 Compiled library will be found in `bin` directory.
 
+#### Web Assembly (WASM)
+
+Web assembly compilation is supported using LLVM WebAssembly backend.
+Installation of LLVM compiler and linker is needed:
+
+```sh
+# apt install clang lld
+```
+
+The webasm object is compiled using:
+```sh
+$ make CC="clang --target=wasm32"
+```
+
 ## Tools
 
 Tools can be all compiled, while invoking `make` as follows :

src/common.h

@@ -22,17 +22,9 @@
 #include <lc3.h>
 #include "fastmath.h"
 
-#include <stdalign.h>
 #include <limits.h>
-
-#ifdef __wasm32__
-#define memmove __builtin_memmove
-#define memset __builtin_memset
-#define memcpy __builtin_memcpy
-#define NULL ((void*)0)
-#else
+#include <stdalign.h>
 #include <string.h>
-#endif
 
 #ifdef __ARM_ARCH
 #include <arm_acle.h>

src/fastmath.h

@@ -20,26 +20,7 @@
 #define __LC3_FASTMATH_H
 
 #include <stdint.h>
-
-#ifdef __wasm32__
-#define log10f __builtin_log10f
-#define sqrtf __builtin_sqrtf
-#define fabsf __builtin_fabsf
-#define floorf __builtin_floorf
-#define fminf __builtin_fminf
-#define fmaxf __builtin_fmaxf
-#define truncf __builtin_truncf
-// This is not exactly roundf, as this return the even value for two equally near
-// values. e.g
-// - roundf(0.5) = 1, nearbyint(0.5) = 0,
-// - roundf(1.5) = 2, nearbyint(1.5) = 2,
-// - roundf(2.5) = 3, nearbyint(2.5) = 2
-// but this builtin maps to https://webassembly.github.io/spec/core/exec/numerics.html#op-fnearest
-#define roundf __builtin_nearbyint
-#define INFINITY __builtin_inff()
-#else
 #include <math.h>
-#endif
 
 
 /**

wasm/math.h

@@ -0,0 +1,37 @@
+/******************************************************************************
+ *
+ *  Copyright 2024 Google LLC
+ *
+ *  Licensed under the Apache License, Version 2.0 (the "License");
+ *  you may not use this file except in compliance with the License.
+ *  You may obtain a copy of the License at:
+ *
+ *  http://www.apache.org/licenses/LICENSE-2.0
+ *
+ *  Unless required by applicable law or agreed to in writing, software
+ *  distributed under the License is distributed on an "AS IS" BASIS,
+ *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *  See the License for the specific language governing permissions and
+ *  limitations under the License.
+ *
+ ******************************************************************************/
+
+#ifndef __LC3_MATH_H
+#define __LC3_MATH_H
+
+#define INFINITY __builtin_inff()
+
+#define floorf  __builtin_floorf
+#define truncf  __builtin_truncf
+
+static inline float roundf(float x)
+{ return x >= 0 ? truncf(x + 0.5f) : truncf(x - 0.5f); }
+
+#define fabsf   __builtin_fabsf
+#define fmaxf   __builtin_fmaxf
+#define fminf   __builtin_fminf
+
+#define log10f  __builtin_log10f
+#define sqrtf   __builtin_sqrtf
+
+#endif /* __LC3_MATH_H */

wasm/string.h

@@ -0,0 +1,28 @@
+/******************************************************************************
+ *
+ *  Copyright 2024 Google LLC
+ *
+ *  Licensed under the Apache License, Version 2.0 (the "License");
+ *  you may not use this file except in compliance with the License.
+ *  You may obtain a copy of the License at:
+ *
+ *  http://www.apache.org/licenses/LICENSE-2.0
+ *
+ *  Unless required by applicable law or agreed to in writing, software
+ *  distributed under the License is distributed on an "AS IS" BASIS,
+ *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *  See the License for the specific language governing permissions and
+ *  limitations under the License.
+ *
+ ******************************************************************************/
+
+#ifndef __LC3_STRING_H
+#define __LC3_STRING_H
+
+#define NULL    ( (void *)0 )
+
+#define memcpy  __builtin_memcpy
+#define memmove __builtin_memmove
+#define memset  __builtin_memset
+
+#endif /* __LC3_STRING_H */